This research has as its immediate objectives the isolation and characterization of the cDNA and gene coding for the collagen chains characteristic of cartilage, Type II collagen. Sufficiently pure Type II collagen mRNA has been isolated from embryonic chick cartilage tissue, to allow the synthesis and cloning of its cDNA. Determination of the base-sequence of this cDNA should give valuable information concerning the structure, codon usage and evolutionary history of the 3' portions of the Type Ii collagen mRNA. This cloned Type Ii collagen cDNA will also be used to screen a chick DNA library to identify and isolate clones containing genomic Type Ii collagen sequences. These cloned genomic sequences will be used to determine the intron-exon arrangement and other structural features of this gene. This information is important in itself, and comparison with the collagen Type I genes may shed light on functional as well as evolutionary relationships. The cloned Type II cDNA and gene fragments, along with cloned Type I cDNAs and gene fragments, will be used to measure the mRNA levels and the mRNA-precursor levels for each collagen chain in cultured cartilage cells that are undergoing a bromodeoxyuridine-induced shift from Type II to Type I collagen synthesis. The long range goal of these studies is to gain more insight into how the expression of the different vertebrate collagen genes is regulated.